1. Field of the Invention
The present invention relates to an electrophoretic display device and a method of manufacturing the same and, more particularly, to an electrophoretic display device that can perform multicolor display by arranging microcapsules encapsulating an electrophoretic ink between a pair of opposing electrode plates one of which is transparent and further including color filters, and a method of manufacturing the same.
2. Description of the Related Art
The recent mainstreams of information display panels are liquid crystal display panels using a backlight. However, the liquid crystal display panels place a heavy load on eyes and are therefore unsuitable to continuous long-time viewing. As a reflection-type display device that puts a little burden on the eyes, there is proposed an electrophoretic display panel including a pair of opposing electrodes and an electrophoretic display layer provided between the electrodes (Jpn. Pat. Appln. KOKOKU Publication No. 50-015115).
This electrophoretic display panel displays a character or an image by reflected light, like a printed sheet surface. For this reason, it places only a light load on the eyes and is suitable to a work of continuously viewing the screen for a long time.
This electrophoretic display panel operates by the principle that an electric field is applied to a dispersion containing charged particles dispersed, thereby moving the charged particles and displaying an image. Out of the electrophoretic display panels, a microcapsule-type electrophoretic display device that encapsulates colored charged particles in microcapsules and arranges the microcapsules between a pair of opposing electrodes is advantageous because of its low driving voltage and high flexibility. Hence, the device has been put into practical use and further developed.
Presently, the mainstream of the electrophoretic display panel is two-color display that is mainly monochrome display from the viewpoint of the structure. The two-color display microcapsule-type electrophoretic display device includes, for example, a microcapsule-type electrophoretic display layer, a transparent electrode, and a transparent base material sequentially above a pixel electrode layer of a substrate including pixel electrodes. In recent years, a color electrophoretic display device capable of performing multicolor display from the two-color display microcapsule-type electrophoretic display device has been demanded.
To make the microcapsule-type electrophoretic display device capable of displaying multicolor display, color filter layers are formed between the microcapsule-type electrophoretic display layer and the transparent electrode, between the transparent electrode and the transparent base material, or above the transparent base material.
When allowing the electrophoretic display device to perform multicolor display by providing the color filter layers, the pattern of the pixel electrodes above the substrate needs to be aligned with the pattern of the color filter layers. However, when bonding a film with the color filter layers formed thereon to the surface of the electrophoretic display device, the alignment to make the pattern of the color filter layers match the pattern of the pixel electrodes above the substrate is difficult, and the productivity lowers.
In addition, if the distance between the patterned color filter layers and the electrophoretic display layer increases, the tint becomes faint in the case of observation from an oblique direction. The electrophoretic display device thus loses its advantage of being less affected by the observation angle.